K-181 Rebuild -- Engine Won't Run

[chesbaycruiser 83]

So I finally got the C-85 donor block machined, and finished rebuilding it to replace the engine in my B-80 that

I have everything all put back together, but I can't get it to run. I have spark, and it will run very briefly if I give it a squirt of starter fluid, but it won't start or run otherwise.

I have confirmed that the fuel pump is working.

I pulled the carb back off, tore it down, cleaned it, and re-installed it. (FYI...it was rebuilt only about a year ago and was working fine when the old engine quit.)

I have considered timing, but I was VERY meticulous about properly meshing the timing marks/gears when I installed the crank, so I don't think that's it. (Plus, the last thing I want to do is pull the thing back off the tractor and tear it down again!)

I'm not sure that the governor is properly adjusted, but I don't know if that would keep the engine from starting or running at all?

Any thoughts, suggestions about diagnosing possible issues or other things to look at would be greatly appreciated.

Thanks,

CB

:banghead:

[WH854 44]

So I finally got the C-85 donor block machined, and finished rebuilding it to replace the engine in my B-80 that

I have everything all put back together, but I can't get it to run. I have spark, and it will run very briefly if I give it a squirt of starter fluid, but it won't start or run otherwise.

I have confirmed that the fuel pump is working.

I pulled the carb back off, tore it down, cleaned it, and re-installed it. (FYI...it was rebuilt only about a year ago and was working fine when the old engine quit.)

I have considered timing, but I was VERY meticulous about properly meshing the timing marks/gears when I installed the crank, so I don't think that's it. (Plus, the last thing I want to do is pull the thing back off the tractor and tear it down again!)

I'm not sure that the governor is properly adjusted, but I don't know if that would keep the engine from starting or running at all?

Any thoughts, suggestions about diagnosing possible issues or other things to look at would be greatly appreciated.

Thanks,

CB

Do you have a shut off valve on the gas tank. If it runs by squirting fuel in the carb sounds like you fuel pump isn't working. Also blow into the tank while you a turning it gver.

Chas

[chesbaycruiser 83]

Do you have a shut off valve on the gas tank. If it runs by squirting fuel in the carb sounds like you fuel pump isn't working. Also blow into the tank while you a turning it gver.

Chas

Chas,

I thought the same thing, but I confirmed that the petcock was open, and I pulled the fuel line off of the carburetor, turned the motor over and confirmed that the fuel pump was pushing plenty of gas.

I'm scratching my head....

:eusa-think:

[specialwheelhorse 174]

Sounds like a fuel issue alright and I don't mean to offend you but since that is

basically a new engine please throw the starting fluid away. If it won't run on a fine

mist of gas it won't run. I have rebuilt at least 25 Kohlers and Tecumsehs and

I don't have a can of that on the place.

Jim in Texas

[chesbaycruiser 83]

Sounds like a fuel issue alright and I don't mean to offend you but since that is

basically a new engine please throw the starting fluid away. If it won't run on a fine

mist of gas it won't run. I have rebuilt at least 25 Kohlers and Tecumsehs and

I don't have a can of that on the place.

Jim in Texas

No offense taken Jim. I'm not a big fan of starter fluid either (and I have been very sparing with it). I just didn't have a good method on hand to spray gas into the carb, so I took the easy route. :hide:

[specialwheelhorse 174]

If the timing, points and ignition are right with fuel it should run.

Many times its apparently a bubble in the line or pump. Does it have comression

Are the valves closing and valve clearance OK.

JIM

[specialwheelhorse 174]

I got a little handy dandy can that puts out a fine mist and a shot or two in the

carb and they are usually off and running. I'm sitting here thinking what in the world

would I do if it was mine. Blowing in the tank is an excellent idea ,

Ive done this many times while turning the engine over.

[specialwheelhorse 174]

Needle valve might be stuck Just thinking !!!!!!

[specialwheelhorse 174]

Run the idle screw in a couple turns. The governor might be holding the throttle tight shut.

You should check to make sure the governor is properly adjusted. Still thinking !!!!!!!

[rmaynard 15,519]

If it runs briefly after using starter fluid, and you have gas pumping out of the pump, then the only thing between you and a running engine is the carburetor.

Turn the engine over a couple of times to pump gas into the carburetor. Then take the bowl off the bottom of the carburetor and see if it is full. My guess is that the float valve is stuck closed.

[specialwheelhorse 174]

Make sure the high speed jet is out a coupel turns.

[chesbaycruiser 83]

Thanks everyone for the great ideas and suggestions.

The battery recharged some, so I worked at it a bit more (using gas this time, not starter fluid!). I got it to run a bit more, but still won't run on it's own. It will occasionally start without priming, but the rough running remains the same.

I'm going recheck the gap on the points. I'm certain I tightened them down good, but I'm willing to try anything that doesn't require tearing the thing down to the crank again.

Bob, I agree with you that it would seem to indicate a carb issue, but everything looked good when I tore it down earlier today...no varnish or sediment. I cleaned it up anyway. it had a rebuild kit installed less than a year ago, and was working great when the engine gave up in December. I may just pull the whole thing off and soak it for 24 hours anyway, just for good measure.

This may be completely unrelated, but when I reinstalled the engine on the tractor, the governor was not adjusted properly. Other than the basic instructions in the K-Series Service Manual, I know nothing about setting and adjusting them. During the reassembly, it was a real challenge getting the throttle cable installed correctly, and now I only seem to have a limited about of throttle lever "throw"...much less than I had before, although it look like the throttle is opening and closing fully.

I'll keep working and report back!

[bowtiebutler956 650]

When you took the carb apart to clean it, was there fuel in the bowl? Matt

[Sparky-(Admin) 21,348]

Theres some great info on carbs and the governors in this thread.

Mike............

[Martin 2,132]

did you try what bob suggested with taking off the bowl and checking if the gas is getting pumped into the bowl?

When you took the carb apart to clean it, was there fuel in the bowl? Matt

x 2...........

[Martin 2,132]

pressurize the tank and make sure the gas is getting into the bowl and filling it. since you say it runs briefly on start fluid, i think you can be fairly sure that gas delivery is your problem. you could also squirt some gas using a small squirt bottle or syringe through the bowl vent into the bowl to fill it. then it should run long enough to let the pump take care of it. sometimes air can be a bear.......

[multihobbyguy 35]

You might check to make sure that the Main Needle Jet is not clogged. Real simple to pull out and make sure it is not plugged.

[skrusins 128]

Bad Gas

[chesbaycruiser 83]

I wasn't able to get back to the tractor last night, so nothing new to report. I will give it a go again today. Just to confirm:

• There was gas in the bowl when I tore it down, and it was all very clean inside. I did use cleaner on the parts, and blew some air through it. I could see through the holes in the needle valve and all appeared clean.
  
• I haven't pressurized the gas tank because my gas flow was already good coming out of the fuel pump.
  
• If I can't get it running today with further carb adjustments, I'll pull the carb again and soak it overnight, just to make sure.
  

Thanks again for all the suggestions! I will report back....

CB

[chesbaycruiser 83]

So, today I:

• Pulled the carb off, cleaned it (again), reinstalled. Same result.
  
• Rechecked and regapped the points. Same result.
  
• Rechecked and regapped the plug. Same result.
  
• Pulled the carb back off, took it to a friend's house to soak in cleaner, brought home a different, freshly rebuilt K-181 carb and installed. Same result.
  
• Confirmed no valves sticking. Good suction through carb, exhaust pumping fine.
  
• Pulled the motor back off, tore it down, and rechecked my work. Timing marks line up perfectly. (see photos)
  
• Put it all back together, installed a new plug. You guessed it. Same result.
  

I give up for today. I need a beer and a good cigar....

More later.

--------

You can see on the teeth where I marked them with a Sharpie to make it easier to see the alignment during assembly.

[can whlvr 993]

its too bad you dont have a different carb to throw on her,i know this sounds a small bit silly but do you have the float the right way in,i put one in backwards once

[illinilefttackle 399]

Just a shot in the dark-but try a completly different spark plug. It has happened to me-it will spark great outside the cylinder, but not under compression-Al

[tunahead72 2,424]

A couple more shots in the dark:

• Did you clean the carb needles separately, then poke through the holes with a tiny wire to make absolutely sure they're clear all the way through?
  
• After you removed and reinstalled the various carbs, did you reconfirm that the fuel pump is still working properly?
  

Good luck!

[chesbaycruiser 83]

its too bad you dont have a different carb to throw on her,i know this sounds a small bit silly but do you have the float the right way in,i put one in backwards once

See post above...I actually did install a different carb today. No joy.

Just a shot in the dark-but try a completly different spark plug. It has happened to me-it will spark great outside the cylinder, but not under compression-Al

Yep. One of the things I did was to install a brand new plug.

Very frustrating. :angry-steamingears:

[smoreau 658]

Pull the fuel line inlet off of the carb, and clean out the carb inlet, I have had one do the same exact thing on a c81 and a small piece of rubber fuel line worked its way up there and even with a two new carb kits I could not get fuel into the carb bowl After removing the nipple I blew air through the seat and a small piece of rubber come flying out. then all was good.